He can only rescue himself Dorthea. Try not to take on his worry or anxiety. He can numb it with drinking but you can't so who ends up feeling more anxious? Us, the one who isn't the alcoholic.
Don't second guess how you offer friendship or support. You do it in a way that you would any other friend. Probably with boundaries and compassion but aware that it is his battle, not yours.
No point in asking him what his plans are. His plan is probably to drink until HE decides he wants to get help. Hopefully sooner rather than later but 7 months of sobriety isn't that long sadly. It is a good start but he may have been pretty bad off before he went sober the last time.
Anyway, there really isn't anything you can do. Hard I know because we care etc but trust us on this, it isn't your job.